This invention relates to current interrupters of the type used in controlling fault currents associated with transmission lines in power distribution systems. More particularly, the invention relates to such interrupters which are explosively activated.
Fast-acting current interrupters are used on power distribution and transmission lines in current limiting circuits. Fault currents on high voltage lines, due to ground shorts, for example, can rapidly become enormous and cause serious equipment damage. As transmission voltages rise, there is a continuing need in the electric power industry for improved current interrupting devices for use in rapidly controlling fault currents.
Current limiting circuits employ current interrupters which open to divert current through an associated current-supressive impedance. The impedance limits the fault current to a safe level. Preferably, the circuit is reestablished as rapidly as possible after the source of the fault is eliminated. In cases of short-lived fault sources such as lightning bolts, the opening and closing of the current interrupter is preferably handled automatically. Upon opening, the interrupter should produce a large voltage drop sufficient to divert the fault current through the associated protective impedance.
One type of explosive interrupter produces a large number of series breaks in the current path through multiple fracturing of a conductive member. Such as interrupter is described in an experimental report entitled Explosive Switch for Interrupting Inductive Circuits, By M. P. Young et al, published by the Naval Research Laboratory and presented at the Pulse Power Systems Workshop, September 1976. Because such explosive interrupters are one-shot devices, it is desireable to provide a system for sequentially installing and removing such interrupters from a current limiting circuit.